A mark and a drainage problem are different observations.
Tell us about leaves, plants or water spilling over an edge if noticed. Include a joint drip or backing-up near a pipe, with the timing in ordinary rain or heavier conditions. An external stain alone does not establish a blocked channel or prove where moisture began. Previous cleaning or repair details may give context without deciding the present condition.
Point out the surface in a photograph if its name is unfamiliar. The outer gutter face, fascia along the roof edge and soffit beneath the overhang are different parts. That makes an exterior washing request clearer while keeping channel debris as its own task.